Fix error when trying to remove and item already being removed.

dist/shuffle.js

@@ -1049,6 +1049,7 @@ return /******/ (function(modules) { // webpackBootstrap
 	  }, {
 	    key: '_movementFinished',
 	    value: function _movementFinished() {
+	      this._transitions.length = 0;
 	      this.isTransitioning = false;
 	      this._dispatchLayout();
 	    }
@@ -1213,50 +1214,51 @@ return /******/ (function(modules) { // webpackBootstrap
 	    value: function remove(collection) {
 	      var _this9 = this;
 	
+	      if (!collection.length) {
+	        return;
+	      }
+	
 	      collection = (0, _arrayUniq2.default)(collection);
 	
-	      var items = collection.map(function (element) {
+	      var oldItems = collection.map(function (element) {
 	        return _this9.getItemByElement(element);
 	      }).filter(function (item) {
 	        return !!item;
 	      });
 	
-	      if (!collection.length) {
-	        return;
-	      }
-	
 	      var handleLayout = function handleLayout() {
 	        _this9.element.removeEventListener(Shuffle.EventType.LAYOUT, handleLayout);
-	        _this9._disposeItems(items);
+	        _this9._disposeItems(oldItems);
 	
 	        // Remove the collection in the callback
 	        collection.forEach(function (element) {
 	          element.parentNode.removeChild(element);
 	        });
 	
-	        // Update things now that elements have been removed.
-	        _this9.items = _this9.items.filter(function (item) {
-	          return !arrayIncludes(items, item);
-	        });
-	        _this9._updateItemCount();
-	
 	        _this9._dispatch(Shuffle.EventType.REMOVED, { collection: collection });
 	
 	        // Let it get garbage collected
 	        collection = null;
-	        items = null;
+	        oldItems = null;
 	      };
 	
 	      // Hide collection first.
 	      this._toggleFilterClasses({
 	        filtered: [],
-	        concealed: items
+	        concealed: oldItems
 	      });
 	
-	      this._shrink(items);
+	      this._shrink(oldItems);
 	
 	      this.sort();
 	
+	      // Update the list of items here because `remove` could be called again
+	      // with an item that is in the process of being removed.
+	      this.items = this.items.filter(function (item) {
+	        return !arrayIncludes(oldItems, item);
+	      });
+	      this._updateItemCount();
+	
 	      this.element.addEventListener(Shuffle.EventType.LAYOUT, handleLayout);
 	    }
 	
@@ -1805,11 +1807,9 @@ return /******/ (function(modules) { // webpackBootstrap
 	  }, {
 	    key: 'applyCss',
 	    value: function applyCss(obj) {
-	      var _this3 = this;
-	
-	      Object.keys(obj).forEach(function (key) {
-	        _this3.element.style[key] = obj[key];
-	      });
+	      for (var key in obj) {
+	        this.element.style[key] = obj[key];
+	      }
 	    }
 	  }, {
 	    key: 'dispose',

src/shuffle-item.js

@@ -39,9 +39,9 @@ class ShuffleItem {
   }
 
   applyCss(obj) {
-    Object.keys(obj).forEach((key) => {
+    for (var key in obj) {
       this.element.style[key] = obj[key];
-    });
+    }
   }
 
   dispose() {

src/shuffle.es6.js

@@ -818,6 +818,7 @@ class Shuffle {
   }
 
   _movementFinished() {
+    this._transitions.length = 0;
     this.isTransitioning = false;
     this._dispatchLayout();
   }
@@ -951,46 +952,47 @@ class Shuffle {
    * @return {Shuffle} The shuffle object
    */
   remove(collection) {
+    if (!collection.length) {
+      return;
+    }
+
     collection = arrayUnique(collection);
 
-    let items = collection
+    let oldItems = collection
       .map(element => this.getItemByElement(element))
       .filter(item => !!item);
 
-    if (!collection.length) {
-      return;
-    }
-
     let handleLayout = () => {
       this.element.removeEventListener(Shuffle.EventType.LAYOUT, handleLayout);
-      this._disposeItems(items);
+      this._disposeItems(oldItems);
 
       // Remove the collection in the callback
       collection.forEach((element) => {
         element.parentNode.removeChild(element);
       });
 
-      // Update things now that elements have been removed.
-      this.items = this.items.filter(item => !arrayIncludes(items, item));
-      this._updateItemCount();
-
       this._dispatch(Shuffle.EventType.REMOVED, { collection });
 
       // Let it get garbage collected
       collection = null;
-      items = null;
+      oldItems = null;
     };
 
     // Hide collection first.
     this._toggleFilterClasses({
       filtered: [],
-      concealed: items,
+      concealed: oldItems,
     });
 
-    this._shrink(items);
+    this._shrink(oldItems);
 
     this.sort();
 
+    // Update the list of items here because `remove` could be called again
+    // with an item that is in the process of being removed.
+    this.items = this.items.filter(item => !arrayIncludes(oldItems, item));
+    this._updateItemCount();
+
     this.element.addEventListener(Shuffle.EventType.LAYOUT, handleLayout);
   }